<!DOCTYPE html>
<html lang="zh-CN">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>Bootstrap 101 Template</title>

    <!-- Bootstrap -->
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css" rel="stylesheet">

    <!-- HTML5 shim 和 Respond.js 是为了让 IE8 支持 HTML5 元素和媒体查询（media queries）功能 -->
    <!-- 警告：通过 file:// 协议（就是直接将 html 页面拖拽到浏览器中）访问页面时 Respond.js 不起作用 -->
    <!--[if lt IE 9]>
      <script src="https://cdn.jsdelivr.net/npm/html5shiv@3.7.3/dist/html5shiv.min.js"></script>
      <script src="https://cdn.jsdelivr.net/npm/respond.js@1.4.2/dest/respond.min.js"></script>
    <![endif]-->
    <style>
        *{
            padding: 0;
            margin: 0;
        }
        .row>div{
            border:1px solid red;
        }
    </style>
  </head>
  <body>
    <h1>你好，世界！</h1>
    <div class="container">
        <div class="row">
            <div class = 'col-lg-2 col-xs-4'>1</div>
            <div class = 'col-lg-2 col-xs-4'>2</div>
            <div class = 'col-lg-2 col-xs-4'>3</div>
            <div class = 'col-lg-2 col-xs-4'>4</div>
            <div class = 'col-lg-2 col-xs-4'>5</div>
            <div class = 'col-lg-2 col-xs-4'>6</div>
            <div class = 'col-lg-2 col-xs-4'>7</div>
            <div class = 'col-lg-2 col-xs-4'>8</div>
            <div class = 'col-lg-2 col-xs-4'>9</div>
            <div class = 'col-lg-2 col-xs-4'>10</div>
            <div class = 'col-lg-2 col-xs-4'>11</div>
            <div class = 'col-lg-2 col-xs-4'>12</div>
        </div>
    </div>

    <!-- 栅格系统，会向上兼容
    举例
    没有大屏和中屏，会直接采用比他们更低一挡的结构，那么会采用小屏的布局方式来排列 -->
  </body>
</html>